Cosmic Ray Spectrum in Supernova Remnant Shocks
Abstract
We performed kinetic simulations of diffusive shock acceleration in Type Ia supernova remnants (SNRs) expanding into a uniform interstellar medium (ISM). The preshock gas temperature is the primary parameter that governs the cosmic ray (CR) acceleration, while magnetic field strength and CR injection rate are secondary parameters. SNRs in the hot ISM, with an injection fraction smaller than 10^{-4}, are inefficient accelerators with less than 10 % energy getting converted to CRs. The shock structure is almost test-particle like and the ensuing CR spectrum can be steeper than E^{-2}. Although the particles can be accelerated to the knee energy of 10^{15.5}Z eV with amplified magnetic fields in the precursor, Alfv'enic drift of scattering centers softens the source spectrum as steep as E^{-2.1} and reduces the CR acceleration efficiency.
Cite
@article{arxiv.1102.3123,
title = {Cosmic Ray Spectrum in Supernova Remnant Shocks},
author = {Hyesung Kang},
journal= {arXiv preprint arXiv:1102.3123},
year = {2011}
}
Comments
8 pages with 5 figures, Proceedings of Astronum 2010 (5th international conference on numerical modeling of space plasma flows), figures are replaced